1. Field of the Invention
The present invention relates to network communications and, more specifically, to restoration path sharing.
2. Description of the Related Art
Advances in wavelength-division multiplexing (WDM) related technologies have started to allow for routing and networking at the optical layer (e.g., optical switch layer) of communications networks, providing a migration toward true optical-layer networking. Optical-layer networking associated with mesh-connected optical networks creates the need for routing wavelength demands over the mesh optical networks and an equivalent need for service recovery in the optical domain in the event of failures.
Traditionally, the optical-layer network provided for fast recovery services, while data networks (e.g., Internet Protocol (IP) networks) were primarily targeted to achieve “best-effort” services. However, with the increasing use of data networks to carry time-critical data (e.g., voice-over-IP (VOIP) data), resiliency and fast recovery of service are becoming important features of data networks as well. Advances in traffic engineering of data networks, such as those covered under the umbrella of multiprotocol label switching (MPLS), have provided a framework for directing the flow of specific services within IP networks.
For both optical-layer networking applications and data networking applications, distribution of topology information, and, in particular, restoration, recovery, and sharing information, is important to the efficient and timely recovery of services. However, many of the restoration and recovery schemes in the prior art fail to provide a compact representation of the relevant information, methods to utilize the data in path calculations in consideration of multiple cost criteria in a way that benefit from sharing of protection link resources, and efficient, distributed mechanisms for making that data available where and when it is needed.